Randomized prospective trial of cooled versus traditional radiofrequency ablation of the medial branch nerves for the treatment of lumbar facet joint pain

Background and objectives No previous study has assessed the outcomes of cooled radiofrequency ablation (C-RFA) of the medial branch nerves (MBN) for the treatment of lumbar facet joint pain nor compared its effectiveness with traditional RFA (T-RFA). This study evaluated 6-month outcomes for pain, function, psychometrics, and medication usage in patients who underwent MBN C-RFA versus T-RFA for lumbar Z-joint pain. Methods In this blinded, prospective trial, patients with positive diagnostic MBN blocks (>75% relief) were randomized to MBN C-RFA or T-RFA. The primary outcome was the proportion of responders' (≥50% Numeric Rating Scale (NRS) reduction) at 6 months. Secondary outcomes included NRS, Oswestry Disability Index (ODI), and Patient Global Impression of Change. Results Forty-three participants were randomized to MBN C-RFA (n=21) or T-RFA (n=22). There were no significant differences in demographic variables (p>0.05). A ≥50% NRS reduction was observed in 52% (95% CI 31% to 74%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.75). A ≥15-point or ≥30% reduction in ODI score was observed in 62% (95% CI 38% to 82%) and 44% (95% CI 22% to 69%) of participants in the C-RFA and T-RFA groups, respectively (p=0.21). Conclusions When using a single diagnostic block paradigm with a threshold of >75% pain reduction, both treatment with both C-RFA and T-RFA resulted in a success rate of approximately 50% when defined by both improvement in pain and physical function at 6-month follow-up. While the success rate was higher in the C-RFA group, this difference was not statistically significant. Trial registration number NCT02478437.